High mobility strained germanium quantum well field effect transistor as the p-channel device option for low power (Vcc = 0.5 V) III&amp;#x2013;V CMOS architecture

MOS-capacitors were fabricated on type II staggered gap strained-Si/strained-Ge heterostructures epitaxially grown on relaxed SiGe substrates of various Ge fractions. Quasistatic quantum mechanical capacitance-voltage (CV) simulations were fit to experimental CV measurements to extract the band alignment of the strained layers. The valence band offset of the strained-Si/strained-Ge heterostructure was found to be 770, 760, and 670 meV for 35, 42, and 52% Ge in the relaxed SiGe substrate, respectively. These values are approximately 100 meV larger than expected on the basis of the usually recommended band offsets for modeling Si/Ge structures. It is shown that the larger valence band offsets found here are consistent with an 800 meV average valence band offset between Si and Ge, which also explains the type II band alignment observed in strained-Si 1-x Ge x on unstrained-Si heterostructures.

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“…Refs. [15][16][17][18][19][20][21][22]. The valence band offset determines the threshold voltage and gate-to-channel capacitance of such devices.…”

Section: Introductionmentioning

confidence: 99%

Extraction of large valence-band energy offsets and comparison to theoretical values for strained-Si/strained-Ge type-II heterostructures on relaxed SiGe substrates

et al. 2012

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“…One enticing approach is to replace the Si channel with high intrinsic hole mobility Ge for p-channel device compared to III-V p-channel material. [8][9][10] Alternative approaches are different surface orientations to improve the carrier mobility, [11][12][13][14] strain engineering, 11,15,16 device architecture, 8,9,17 and optimal channel direction. [19][20][21][22][23] Research efforts are currently devoted towards investigation of the Ge as channel material, since higher intrinsic carrier mobility of Ge can provide a larger drive current, and its smaller bandgap can enable operation at a lower voltages.…”

Section: Introductionmentioning

confidence: 99%

Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy

Hudait

Zhu

Maurya

et al. 2013

Journal of Applied Physics

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Structural and band alignment properties of atomic layer Al2O3 oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al2O3 film and the Ge epilayer. The extracted valence band offset, ΔEv, values of Al2O3 relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in ΔEv related to the crystallographic orientation were ΔEV(110)Ge>ΔEV(100)Ge≥ΔEV(111)Ge and the conduction band offset, ΔEc, related to the crystallographic orientation was ΔEc(111)Ge>ΔEc(110)Ge>ΔEc(100)Ge using the measured ΔEv, bandgap of Al2O3 in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design.

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“…1 One attractive approach is to replace the Si channel with high intrinsic hole mobility Ge for p-channel and low effective carrier mass III-V material for n-channel material. [2][3][4][5] Alternative approach is different surface orientations to improve carrier mobility [6][7][8][9] and optimal channel direction for device speed. [10][11][12][13][14] Recently, semiconductor industry was replaced SiO 2 gate oxide by hafnium-based gate dielectric on Si complementary metal oxide semiconductor (CMOS) technology and demonstrated superior microprocessor performance compared to SiO 2 gate oxide.…”

Section: Introductionmentioning

confidence: 99%

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

Hudait

Zhu

2013

Journal of Applied Physics

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Articles you may be interested inLow-temperature plasma-enhanced atomic layer deposition of HfO2/Al2O3 nanolaminate structure on Si J. Vac. Sci. Technol. B 33, 01A101 (2015) Crystallographically oriented epitaxial Ge layers were grown on (100), (110), and (111)A GaAs substrates by in situ growth process using two separate molecular beam epitaxy chambers. The band alignment properties of atomic layer hafnium oxide (HfO 2 ) film deposited on crystallographically oriented epitaxial Ge were investigated using x-ray photoelectron spectroscopy (XPS). Valence band offset, DE v values of HfO 2 relative to (100)Ge, (110)Ge, and (111)Ge orientations were 2.8 eV, 2.28 eV, and 2.5 eV, respectively. Using XPS data, variation in valence band offset, DE V ð100ÞGe > DE V ð111ÞGe > DE V ð110ÞGe, was obtained related to Ge orientation. Also, the conduction band offset, DE c relation, DE c ð110ÞGe > DE c ð111ÞGe > DE c ð100ÞGe related to Ge orientations was obtained using the measured bandgap of HfO 2 on each orientation and with the Ge bandgap of 0.67 eV. These band offset parameters for carrier confinement would offer an important guidance to design Ge-based p-and n-channel metal-oxide field-effect transistor for low-power application.

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High mobility strained germanium quantum well field effect transistor as the p-channel device option for low power (Vcc = 0.5 V) III–V CMOS architecture

Cited by 96 publications

References 4 publications

Extraction of large valence-band energy offsets and comparison to theoretical values for strained-Si/strained-Ge type-II heterostructures on relaxed SiGe substrates

Extraction of large valence-band energy offsets and comparison to theoretical values for strained-Si/strained-Ge type-II heterostructures on relaxed SiGe substrates

Structural and band alignment properties of Al2O3 on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy

Energy band alignment of atomic layer deposited HfO2 oxide film on epitaxial (100)Ge, (110)Ge, and (111)Ge layers

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